Heat pipe, electronic device, instrument, and method for manufacturing heat pipe

Abstract

The present invention efficiently circulates heat irrespective of the orientation in which a heat pipe (20) is used. The heat pipe (20) comprises: a pipe body (21) in which a working fluid is sealed; a sintered body layer (22) formed by sintering a metal powder on the inner wall surface (21a) of the pipe body (21); an evaporation part (201) at which the working fluid evaporates; a condensation part (202) at which the working fluid condenses; and an intermediate part (203) located between the evaporation part (201) and the condensation part (202). At least the intermediate part (203) includes, in a cross section obtained by cutting the same in a direction intersecting the extending direction of the heat pipe (20), a first thickness section having a first thickness (t1) and a second thickness section having a second thickness (t2). The second thickness (t2) is more than the first thickness (t1). The first and second thickness sections in the intermediate part (203) at least partially face each other across the center of the pipe body (21). The second thickness section is formed by a combination of the pipe body (21) and the sintered body layer (22).

Description

Heat pipe, electronic device, appliance, and method for manufacturing heat pipe

[0001] The present disclosure relates to heat pipes, electronic devices, appliances, and methods for manufacturing heat pipes.

[0002] As disclosed in Patent Document 1, electronic devices such as game consoles, personal computers, and server computers are equipped with cooling fans, heat sinks, heat pipes, and other components that cool heat-generating components on circuit boards. Furthermore, as disclosed in Patent Document 2, a wick made of sintered metal powder is provided on the inner wall of the heat pipe. The working fluid sealed in the heat pipe circulates by utilizing capillary action in the wick.

[0003] International Publication No. 2021 / 193879 Japanese Patent Application Laid-Open No. 2002-318085

[0004] However, since the working fluid enclosed in the heat pipe is affected by gravity, the circulation efficiency may change depending on the position of use. Therefore, there is a demand for a heat pipe that can maintain heat circulation efficiency regardless of the position of use.

[0005] An object of the present disclosure is to provide a heat pipe, an electronic device, an appliance, and a method for manufacturing a heat pipe that are capable of efficiently circulating heat regardless of the position of use.

[0006] The heat pipe proposed in the present disclosure is a heat pipe including a tubular body that seals a working fluid and a sintered body layer formed by sintering metal powder onto the inner wall surface of the tubular body, and includes an evaporation section in which the working fluid evaporates, a condensation section in which the working fluid condenses, and an intermediate section located between the evaporation section and the condensation section, and at least the intermediate section includes, in a cross section cut in a direction intersecting the extension direction of the heat pipe, a first thick section that is a first thickness and a second thick section that is a second thickness, the second thickness being thicker than the first thickness, at least a portion of the first thick section and the second thick section in the intermediate section facing each other across the center of the tubular body on the cross section, and the second thick section consisting of a combination of the tubular body and the sintered body layer.

[0007] The electronic device proposed in the present disclosure is an electronic device that accommodates within a housing a heat-generating component, a heat-dissipating component, a heat pipe including a tube that seals a working fluid, and a sintered body layer formed by sintering metal powder on the inner wall surface of the tube, wherein the heat pipe includes an evaporation section in which the working fluid evaporates due to heat from the heat-generating component, a condensation section in which the working fluid condenses due to the heat dissipation effect of the heat-dissipating component, and an intermediate section located between the evaporation section and the condensation section, and at least the intermediate section includes, in a cross section cut in a direction intersecting the extension direction of the heat pipe, a first thick section that is a first thickness and a second thick section that is a second thickness, the second thickness being thicker than the first thickness, and at least a portion of the first thick section and the second thick section in the intermediate section are opposed via the center of the tube on the cross section, and the second thick section is made up of a combination of the tube and the sintered body layer.

[0008] The device proposed in the present disclosure is a device used for forming a sintered body layer in a heat pipe including a tube that seals a working fluid and a sintered body layer formed by sintering metal powder onto the inner wall surface of the tube, and includes a first extension portion that extends in the direction in which the tube extends, and a second extension portion that extends from the end of the first extension portion in the direction in which the tube extends, and the length from the center of the second extension portion to the outer wall surface in a cross section cut in a direction intersecting the extension direction of the second extension portion is shorter than the length from the center of the first extension portion to the outer wall surface in a cross section cut in a direction intersecting the extension direction of the first extension portion, and the length from the center of the first extension portion to the outer wall surface of the cross section cut in the direction intersecting the extension direction of the first extension portion is partially shorter in the first extension portion.

[0009] The method for manufacturing a heat pipe proposed in the present disclosure is a method for manufacturing a heat pipe including a tube that seals a working fluid and a sintered body layer formed by sintering metal powder onto the inner wall surface of the tube, and includes the steps of inserting an appliance extending in the extension direction of the tube into the tube, filling the gap between the inner wall surface of the tube and the outer wall surface of the appliance with metal powder, and forming the sintered body layer in the gap by sintering the metal powder, wherein the gap includes a first filling region and a second filling region, the second filling region has a width in the thickness direction of the tube that is wider than the first filling region, and the first filling region includes a region that is partially wider in the thickness direction of the tube.

[0010] 3B and 6. FIG. 6 is a cross-sectional view showing a cross section of a heat pipe taken along the IV-IV cutting line shown in FIG. 3B and FIG. 6. FIG. 7 is a cross-sectional view showing a cross section of a heat pipe taken along the V-V cutting line shown in FIG. 3B. FIG. 7 is a cross-sectional view showing a cross section of a heat pipe taken along the V-V cutting line shown in FIG. 3B. FIG. 8 is a cross-sectional view showing a schematic example of a modified heat pipe. FIG. 9 is a cross-sectional view showing a schematic example of another modified heat pipe. FIG. 10 is a perspective view showing an apparatus used to form a sintered body layer. FIG. 11 is a diagram showing a schematic view of filling metal powder. FIG. 12 is a cross-sectional view showing a state in which metal powder is filled into a tube.

[0011] The electronic device proposed in this disclosure will be described below with reference to the drawings. FIG. 1A is a perspective view showing an example of an electronic device in a vertical position. FIG. 1B is a perspective view showing an example of an electronic device in a horizontal position. FIG. 2 is a plan view showing components arranged in a housing of the device body. In the following description, the arrow G shown in each figure indicates the direction in which gravity acts (hereinafter referred to as the gravity direction G). In addition, in each figure, the side facing the gravity direction G is referred to as the bottom side, and the opposite side is referred to as the top side.

[0012] [Electronic Device] The electronic device according to this embodiment may be a game device, a personal computer, a server computer, or the like. Figures 1A and 1B show a game device as an example of an electronic device. As shown in Figures 1A and 1B, the electronic device 10 may have a device main body 11 and a first cover 12 and a second cover 13 that cover the device main body 11. As shown in these figures, the first cover 12 and the second cover 13 may be sized to cover the entire device main body 11, or may be sized to cover only a portion of the device main body 11.

[0013] [Vertical and Horizontal Orientations of Electronic Device] The electronic device 10 is preferably usable in at least two usage orientations. The usage orientation is the orientation of the electronic device 10 when used by a user. The electronic device 10 can be placed in the vertical orientation shown in FIG. 1A and the horizontal orientation shown in FIG. 1B.

[0014] In this specification, the vertical position refers to a position in which at least a portion of the tube 21 of the heat pipe 20 (described later) extends substantially along the direction of gravity G, with the evaporator 201 located below and the condenser 202 located above. The horizontal position refers to a position in which at least a portion of the tube 21 of the heat pipe 20 extends in a direction (substantially horizontal) that intersects with the direction of gravity G. In the horizontal position, the electronic device 10 is positioned such that the second cover 13 is on the lower side.

[0015] When electronic device 10 is in a horizontal position, it may be structured so that it can be placed directly on a surface (placement surface) such as a desk or floor and be stably supported, or it may be structured so that it can be stably supported on a placement surface by attaching a stand member (not shown) to electronic device 10. Similarly, when electronic device 10 is in a vertical position, it may be structured so that it can be placed directly on a placement surface and be stably supported, or it may be structured so that it can be stably supported on a placement surface by attaching a stand member (not shown) to electronic device 10.

[0016] [Device Main Body] The device main body 11 has a housing 11a. As shown in FIG. 2, the housing 11a houses the heat pipe 20, the cooling fan 50, the power supply unit 60, and heat sinks 71, 72, and 73, which are heat dissipation components. The housing 11a also houses a circuit board (not shown). An electronic component that generates heat (a heat-generating component 80 shown in FIG. 3A and the like, which will be described later) is mounted on the circuit board. The electronic component that generates heat may be a CPU (Central Processing Unit), a GPU (Graphical Processing Unit), or the like.

[0017] The power supply unit 60 uses current supplied from an external power source to supply drive power to various components, such as the CPU, of the device main body 11. The power supply unit 60 has a case 61. Inside the case 61, a circuit board having a transformer, a rectifier circuit, etc. is housed.

[0018] The heat sinks 71, 72, and 73 are connected directly to heat-generating components such as a CPU, or are thermally connected to the heat-generating components via a heat-receiving block or heat pipe 20. The heat sinks 71, 72, and 73 may have a shape including, for example, a plurality of heat dissipation fins. The cooling fan 50 forms an airflow that passes through the inside of the case 61 of the power supply unit 60 and through the heat sinks 71, 72, and 73.

[0019] [Heat Pipe] Next, the configuration and function of the heat pipe 20 will be described with reference to Figures 3A to 5. Figure 3A is a cross-sectional view schematically showing the heat pipe and its peripheral components when the electronic device is in a vertical position. Figure 3B is a cross-sectional view schematically showing the heat pipe and its peripheral components when the electronic device is in a horizontal position. Figure 4 is a cross-sectional view showing a cross section of the heat pipe taken along the IV-IV section line shown in Figure 3B. Figure 5 is a cross-sectional view showing a cross section of the heat pipe taken along the V-V section line shown in Figure 3B. Note that the arrows shown in the tube 21 in Figures 3A and 3B represent the circulation of the working fluid sealed in the tube 21.

[0020] The heat pipe 20 includes a tube 21 that encloses a working fluid, and a sintered layer 22 that is formed by sintering metal powder onto the inner wall surface 21a of the tube 21. Sintering refers to baking a solidified powdered metal at a high temperature that is lower than the melting point.

[0021] The material of the tube 21 is not particularly limited, but is preferably a metal with high thermal conductivity. The working fluid may be selected appropriately depending on the material of the tube 21, and is preferably water, for example.

[0022] It is preferable that at least a portion of the tube 21 is arranged so as to be generally aligned with the direction of gravity when the electronic device 10 is in a vertical position. 3A and 3B show a configuration in which the tube 21 extends straight in one direction, but this is not limiting, and a portion of the tube 21 may be bent or twisted.

[0023] The sintered body layer 22 may be formed by, for example, sintering copper powder. In the following description, the sintered body layer will be denoted by the reference numerals "22a" and "22b" depending on the part where it is formed, but will simply be referred to as the "sintered body layer 22" unless there is a particular need to distinguish between them.

[0024] The heat pipe 20 includes an evaporation section 201, a condensation section 202, and an intermediate section 203. The evaporation section 201, the condensation section 202, and the intermediate section 203 indicate parts of the heat pipe 20, and are preferably configured as a continuous connected structure rather than being physically separated.

[0025] The evaporation section 201 is a section that is arranged so that at least a part of its outer surface is in contact with the heat-generating component 80, and is a section where the working fluid evaporates due to the heat of the heat-generating component 80. Note that the evaporation section 201 is not limited to a section where the tube 21 is arranged so that it is in direct contact with the heat-generating component 80, as long as it is arranged so that the working fluid sealed in the tube 21 evaporates due to at least the heat from the heat-generating component 80.

[0026] The condenser section 202 is a section where at least a part of the outer surface is arranged in contact with the heat sink 73, and where the working fluid is condensed by the heat dissipation effect of the heat sink 73. Note that the condenser section 202 is not limited to a section where the tube 21 is arranged in direct contact with the heat sink 73, as long as the working fluid sealed in the tube 21 is arranged so that it is condensed by at least the heat dissipation effect of the heat sink 73.

[0027] The intermediate section 203 is a section disposed between the evaporation section 201 and the condensation section 202. That is, one end of the heat pipe 20 is the evaporation section 201, and the other end is the condensation section 202, with the intermediate section 203 being between the evaporation section 201 and the condensation section 202.

[0028] The working fluid present in the evaporation section 201 is heated by the heat of the heat-generating component 80 and vaporizes. The vaporized working fluid moves to the condensation section 202 through the intermediate section 203. In the heat pipe 20, the inside of the tube body 21 and the sintered body layer 22 is hollow (hereinafter referred to as hollow section C). The hollow section C serves as a flow path through which the vaporized working fluid moves.

[0029] The working fluid that has moved to the condenser section 202 condenses and liquefies due to the heat dissipation effect of the heat sink 73. The liquefied working fluid then creeps along the inner wall of the heat pipe 20 and moves to the evaporator section 201 through the intermediate section 203. The working fluid that has moved to the evaporator section 201 is then heated by the heat from the heat-generating component 80 and vaporizes. In this way, in the heat pipe 20, the working fluid is circulated within the tubular body 21, thereby carrying heat from the evaporator section 201 to the condenser section 202 and suppressing the temperature rise of the heat-generating component 80.

[0030] In the heat pipe 20, a sintered body layer 22 is formed on the inner wall surface 21a of the tube body 21 in order to move the liquefied working fluid from the condenser section 202 to the evaporator section 201. The sintered body layer 22 has a large number of voids formed therein according to the shape, particle size, etc. of the metal powder to be sintered. The liquefied working fluid can move within the sintered body layer 22 due to the capillary force of the sintered body layer 22. That is, the liquefied working fluid can move from the condenser section 202 to the evaporator section 201 through the voids in the sintered body layer 22.

[0031] When the electronic device 10 is in a vertical position, the direction of movement of the working fluid from the condenser 202 to the evaporator 201 coincides with the direction of gravity G, and therefore the working fluid can move smoothly due to the influence of gravity in addition to the capillary force. On the other hand, when the electronic device 10 is in a horizontal position, the direction of movement from the condenser 202 to the evaporator 201 differs from the direction of gravity G, and therefore the working fluid moves less easily than when the electronic device 10 is in a vertical position.

[0032] Furthermore, in the circulation of the working fluid, the movement of the vaporized working fluid from the evaporator 201 to the condenser 202 and the movement of the liquefied working fluid from the condenser 202 to the evaporator 201 occur in parallel. In other words, in the circulation of the working fluid, the movement of the vaporized working fluid from the evaporator 201 to the condenser 202 and the movement of the liquefied working fluid from the condenser 202 to the evaporator 201 are counterflows. Therefore, the vaporized working fluid generates a force that acts as resistance to the movement of the liquefied working fluid. Therefore, the circulation of the working fluid may be affected depending on the flow rate of the vaporized working fluid.

[0033] 5, the heat pipe 20 has a configuration in which the intermediate portion 203 includes a first thick portion having a first thickness t1 and a second thick portion having a second thickness t2 in a cross section cut in a direction perpendicular to (intersecting with) the extension direction of the tube body 21. Note that the thickness of the tube body 21 may be the same regardless of the location.

[0034] In this embodiment, the second thick portion is a portion consisting of the combination of the tube 21 and the sintered body layer 22a. That is, the thickness t2 is the sum of the thickness of the tube 21 and the thickness of the sintered body layer 22a. On the other hand, the first thick portion is a portion consisting of only the tube 21. That is, the thickness t1 is the thickness of the tube 21 itself. Therefore, the second thickness t2 of the second thick portion is thicker than the first thickness t1 of the first thick portion. As described above, in the heat pipe 20, the sintered body layer 22 is formed on a predetermined portion of the inner wall surface 21a of the intermediate portion 203. In other words, in the heat pipe 20, the intermediate portion 203 includes a portion of the inner wall surface 21a where the sintered body layer 22 is not formed.

[0035] Since there is a portion where the sintered body layer 22a is not formed, the inner diameter of the hollow portion C in the intermediate portion 203 is relatively wide. That is, the flow path in the intermediate portion 203 is wider than in a configuration where the sintered body layer 22 is formed around the entire circumference of the inner wall surface 21a. Therefore, the flow rate of the vaporized working fluid in the intermediate portion 203 is slower than in a configuration where the sintered body layer 22 is formed around the entire circumference.

[0036] Furthermore, in the heat pipe 20, as shown in FIGS. 3B and 5, the sintered body layer 22a is formed so as to be located only below the intermediate portion 203 when the electronic device 10 is in a horizontal position.

[0037] When the electronic device 10 is in a horizontal position, the working fluid liquefied in the condenser 202 moves to the lower part of the heat pipe 20 due to the influence of gravity. Therefore, the working fluid moves to the evaporator 201 due to the capillary force of the sintered body layer 22a formed in the lower part of the intermediate part 203.

[0038] 5 shows an example in which sintered body layer 22a is formed at the lower part of intermediate portion 203 with a predetermined width in the circumferential direction, but the shape of sintered body layer 22a is not limited to this. It is preferable that at least a portion of sintered body layer 22a is formed at the lowermost part of inner wall surface 21a of tube 21 in intermediate portion 203 when electronic device 10 is in a horizontal position. In other words, it is preferable that second thick portion having thickness t2 is provided to include at least the lowermost part of tube 21 in intermediate portion 203 when electronic device 10 is in a horizontal position.

[0039] Furthermore, sintered body layer 22a is preferably formed so as to be located below center O1 of tube 21 when electronic device 10 is in a horizontal position. That is, second thick portion having thickness t2 is preferably formed so as to be located below center O1 (see FIG. 5) of tube 21 on a cross section taken in a direction perpendicular to the extension direction of tube 21 when electronic device 10 is in a horizontal position. Furthermore, sintered body layer 22a is preferably formed, for example, in tube 21 having a circular cross section, in a range in which central angle θ shown in FIG. 5 is equal to or greater than 120° and less than 180°.

[0040] The condenser section 202 preferably includes a first thick portion having a first thickness t1 and a second thick portion having a second thickness t2 in a cross section taken in a direction perpendicular to the extension direction of the tube 21. The second thick portion of the intermediate section 203 preferably is connected to the second thick portion of the condenser section 202. That is, the sintered body layer 22a of the intermediate section 203 and the sintered body layer 22a of the condenser section 202 are preferably formed substantially flush with each other without any steps in the extension direction. In this way, by making the thickness of the condenser section 202 the same as that of the intermediate section 203, the flow path of the working fluid can be widened.

[0041] As shown in FIG. 4 , the sintered body layer 22b formed on the inner wall surface 21a of the evaporation section 201 may be formed over the entire circumference on a cross section taken in a direction perpendicular to the extension direction of the tube 21. Also, as shown in FIGS. 3A and 3B , the sintered body layer 22b formed on the inner wall surface 21a of the evaporation section 201 may be formed over the entire length of the evaporation section 201 in the extension direction of the tube 21. The evaporation section 201 may also have a third thick portion having a third thickness t3. The third thick portion is formed by combining the tube 21 and the sintered body layer 22b and is thicker than the second thick portion having the second thickness t2. That is, the thickness of the sintered body layer 22b formed on the inner wall surface 21a of the tube 21 in the evaporation section 201 may be thicker than the thickness of the sintered body layer 22a formed on the inner wall surface 21a of the tube 21 in the intermediate portion 203.

[0042] However, the shape of the sintered body layer 22b formed on the inner wall surface 21a of the tube body 21 in the evaporation section 201 is not limited to the example shown in the figure, and even in the evaporation section 201, the sintered body layer 22b may be formed only on the lower part when the electronic device 10 is in a horizontal position.

[0043] 3A and other figures, the intermediate portion 203 preferably includes a third thick portion having a third thickness t3 in at least a portion on the evaporation portion 201 side. The third thick portion of the intermediate portion 203 may be connected to the third thick portion of the evaporation portion 201. That is, the third thick portion may be provided not only in the evaporation portion 201 but also in the intermediate portion 203. In this way, by forming the sintered body layer 22 thick in an area susceptible to resistance from the vaporized working fluid, the liquefied working fluid can more easily return to the evaporation portion 201. As a result, the circulation of the working fluid is smoother.

[0044] 5, it is preferable that at least a portion of the first thick portion and the second thick portion in the intermediate portion 203 face each other across the center O1 of the tube 21. In other words, it is preferable that the cross-sectional shape of the intermediate portion 203 is asymmetrical with respect to the center O1 of the tube 21.

[0045] In addition, in the present embodiment, the heat pipe 20 is provided in the electronic device 10 used in a vertical or horizontal position, but this is not limiting. For example, the heat pipe 20 may be provided in an electronic device used in one of the positions. In this case, the position in which the electronic device is used may be the horizontal position described in the present embodiment.

[0046] In addition, although the present embodiment has been described with reference to an example in which the tube 21 has a circular cross-sectional shape, the cross-sectional shape of the tube 21 is not limited to this. That is, the cross-sectional shape of the tube 21 may be elliptical or rectangular.

[0047] Although not shown, it is preferable that a plurality of grooves extending in the extension direction of the tube 21 are formed on the inner wall surface 21a of the tube 21 in each of the evaporation section 201, the condensation section 202, and the intermediate section 203. It is also preferable that a sintered body layer 22 is formed on the plurality of grooves formed on the inner wall surface 21a of the tube 21. Since capillary force can also be generated in the plurality of grooves, the movement of the liquefied working fluid can be made smoother.

[0048] [Summary] As described above, in the heat pipe 20 according to this embodiment, the flow path of the working fluid can be made relatively wide without increasing the diameter of the tube 21 itself. Therefore, the flow rate of the vaporized working fluid moving from the evaporator 201 to the condenser 202 can be made relatively slow. Furthermore, because the sintered body layer 22 is formed on the lower part of the tube 21 when the electronic device 10 is in a horizontal position, the working fluid can easily move due to capillary force even when the electronic device 10 is in a horizontal position. Therefore, the liquefied working fluid can smoothly move from the condenser 202 to the evaporator 201. As a result, heat circulation can be efficiently achieved regardless of the position of the electronic device 10.

[0049] Furthermore, in the heat pipe 20 according to this embodiment, the amount of metal powder used to form the sintered body layer 22 can be reduced compared to a configuration in which the sintered body layer 22 is formed on the entire periphery of the inner wall surface 21a of the tube body 21. Therefore, the manufacturing cost can be reduced.

[0050] [Modifications] Fig. 6 is a diagram schematically showing an example of a modification of the heat pipe, and Fig. 7 is a diagram schematically showing another example of a modification of the heat pipe.

[0051] FIG. 3A and other figures relating to this embodiment show an example in which the position and thickness of the sintered body layer 22 in the condenser section 202 are the same as those in the intermediate section 203. However, this is not limited thereto. For example, as shown in FIG. 6 , the sintered body layer 22 may not be formed in a portion of the condenser section 202. Furthermore, although not shown, a sintered body layer thinner than the sintered body layer 22a formed in the intermediate section 203 may be formed in the condenser section 202. That is, the thickness of the combination of the tube 21 and the sintered body layer 22 may gradually decrease from the evaporator section 201 side toward the condenser section 202 side. This configuration can further widen the flow path of the vaporized working fluid. As a result, the flow rate of the vaporized working fluid can be slowed, and the liquefied working fluid can be smoothly moved. Furthermore, the amount of metal powder used to form the sintered body layer 22 can be reduced, thereby reducing manufacturing costs.

[0052] 3A and other figures relating to this embodiment show an example in which the sintered body layer 22a is not formed in a portion of the intermediate portion 203. However, this is not limited thereto. For example, as shown in FIG. 7, the sintered body layer 22a may be formed around the entire circumferential circumference of the tube 21 in the intermediate portion 203. That is, the first thick portion having the first thickness t1 in the intermediate portion 203 may be formed by combining the tube 21 and the sintered body layer 22a. That is, the sintered body layer 22a may be formed around the entire circumferential circumference of the intermediate portion 203 and may have a thickness that varies in part in the circumferential direction, so as to include a portion that is thinner than other portions. As shown in FIG. 7, the first thick portion and the second thick portion in the intermediate portion 203 may at least partially face each other across the center of the tube 21. That is, the cross-sectional shape of the intermediate portion 203 may be asymmetric with the center of the tube 21 as the center of symmetry. 7, the second thick portion having the second thickness t2 is preferably disposed downward when the electronic device 10 is in a horizontal position. This configuration allows the flow path of the vaporized working fluid to be relatively wide, and also allows the capillary force of the sintered body layer 22 to be generated around the entire circumference of the tube body 21. This allows for efficient heat circulation.

[0053] [Method of Manufacturing Heat Pipe] Next, a method of manufacturing a heat pipe will be described with reference to Figures 8A to 8C. Figure 8A is a perspective view showing an apparatus used to form a sintered body layer. Figure 8B is a diagram showing a schematic diagram of filling metal powder. Figure 8C is a diagram showing a state in which metal powder has been filled into the tube, and is a IIX-IIX cross section shown in Figure 8B. Note that the dashed line in Figure 8C is an imaginary line indicating a second extension portion 92, which will be described later.

[0054] Here, a method for manufacturing a heat pipe will be described in which the sintered layer 22a is formed around the entire circumferential circumference of the tube body 21 in the intermediate portion 203, similar to the heat pipe 20 shown in Fig. 7. Note that O2 shown in Figs. 8A to 8C is the center of the device 90 in a cross section cut in a direction perpendicular to the extension direction of the device 90.

[0055] In the manufacturing process of the heat pipe, a tool 90 shown in Fig. 8A is used to form the sintered body layer 22. The tool 90 is used as a mold when forming the sintered body layer 22. The tool 90 preferably has a shape that extends in the extension direction of the tube 21 and a size that allows it to be inserted into the tube 21.

[0056] The device 90 includes a first extension portion 91 and a cylindrical second extension portion 92. The first extension portion 91 has a shape that extends in the same direction as the tubular body 21. The second extension portion 92 has a shape that extends from an end of the first extension portion 91 in the same direction as the first extension portion 91, and is a portion with a smaller diameter than the first extension portion 91. That is, as shown in FIG. 8C , a length r2 from the center O2 of the device 90 to an outer wall surface 92a of the second extension portion 92 is shorter than lengths r11 and r12 from the center O2 of the device 90 to the outer wall surface 91a on a cross section cut in a direction intersecting the extension direction of the device 90.

[0057] Furthermore, the first extension portion 91 includes a portion where the length from the center O2 of the instrument 90 to the outer wall surface 91a is partially short in a cross section taken in a direction perpendicular to the extension direction of the instrument 90. Specifically, as shown in Fig. 8C, the length from the center O2 of the first extension portion 91 to the outer wall surface 91a is r11 in some portions and is r12, which is shorter than r11, in other portions. That is, the outer wall surface 91a of the first extension portion 91 has a shape including a first outer peripheral surface 911a having a radius r11 and a second outer peripheral surface 912a having a radius r12, and the radius of the second outer peripheral surface 912a (second radius) is smaller than the radius of the first outer peripheral surface 911a (first radius).

[0058] First, as shown in FIG. 8B , the tool 90 is inserted into the tube 21. The tool 90 is preferably inserted so that its center O2 coincides with the center O1 of the tube 21. In this state, a gap is formed between the tube 21 and the tool 90. Specifically, a first filling region F1 filled with metal powder is formed between the inner wall surface 21a of the tube 21 and the outer wall surface 91a of the first extension portion 91. Furthermore, a second filling region F2 filled with metal powder is formed between the inner wall surface 21a of the tube 21 and the outer wall surface 92a of the second extension portion 92. The second filling region F2 has a width in the thickness direction of the tube 21 that is wider than the first filling region F1. The first filling region F1 includes a region that is partially wider in the thickness direction of the tube 21.

[0059] 8B , the first filling region F1 is a region for forming the sintered body layer 22 in the entire condenser section 202 and part of the intermediate section 203 of the heat pipe. The second filling region F2 is a region for forming the sintered body layer 22 in the entire evaporator section 201 and part of the intermediate section 203 of the heat pipe.

[0060] 8B , the device 90 is preferably inserted into the tube 21 so that the first extension portion 91 is positioned lower than the second extension portion 92 in the direction of gravity G. The tube 21 and the device 90 are preferably fixed so that their relative positions do not change when the device 90 is inserted into the tube 21. Although not shown in the drawings, the lower end of the tube 21 in the direction of gravity may be terminally treated by, for example, swaging.

[0061] Next, metal powder is filled into the first filling region F1 and the second filling region F2. The arrows in FIG. 8B indicate the direction of movement of the metal powder when filling. That is, in the example shown in FIG. 8B, the metal powder is poured from the second extension portion 92 side in the extension direction of the tool 90. The metal powder is first filled into the first filling region F1, and then into the second filling region F2. Then, the filling can be completed by applying vibration to the entire device.

[0062] The fixture 90 is then sintered to form the sintered body layer 22. After sintering, the fixture 90 can be removed from the tube 21. As a result, the metal powder filled in the first filling region F1 becomes the sintered body layer 22a in the first and second thick portions. The metal powder filled in the second filling region F2 becomes the sintered body layer 22b in the third thick portion.

[0063] The shape and size of the fixture 90 are not limited to those shown in Fig. 8A . For example, when manufacturing the heat pipe 20 shown in Fig. 3A , it is preferable that the diameter of the portion of the first extension portion 91 of the fixture 90 that forms the first thick portion is the same as the diameter of the inner wall surface 21a of the tube 21. In other words, it is preferable that the length r11 from the center O2 of the first extension portion 91 to the outer wall surface 91a is the same as the inner diameter of the tube 21. Furthermore, the fixture 90 is not limited to being made of a single member, but may be made of multiple members that form the first filling region F1 and the second filling region F2.

[0064] [Note] For example, the heat pipe, electronic device, appliance, and method for manufacturing a heat pipe may have the following configurations: (1) A heat pipe including a tubular body that encloses a working fluid and a sintered body layer formed by sintering a metal powder on the inner wall surface of the tubular body, the heat pipe including an evaporation section where the working fluid evaporates, a condensation section where the working fluid condenses, and an intermediate section located between the evaporation section and the condensation section, at least the intermediate section includes a first thick section having a first thickness and a second thick section having a second thickness in a cross section taken in a direction intersecting an extension direction of the heat pipe, the second thickness being greater than the first thickness, at least a portion of the first thick section and the second thick section in the intermediate section facing each other across the center of the tubular body in the cross section, and the second thick section being a combination of the tubular body and the sintered body layer. (2) A heat pipe as set forth in (1), wherein the first thick portion is formed by a combination of the tubular body and the sintered body layer. (3) A heat pipe as set forth in (1), wherein the first thick portion is formed only by the tubular body. (4) A heat pipe as set forth in any one of (1) to (3), wherein at least the evaporation section has a third thick portion having a third thickness, the third thick portion being formed by a combination of the tubular body and the sintered body layer and being thicker than the second thick portion. (5) A heat pipe as set forth in (4), wherein the intermediate section includes the third thick portion in at least a portion on the evaporation section side. (6) A heat pipe as set forth in (4) or (5), wherein the third thick portion of the intermediate section is connected to the third thick portion of the evaporation section. (7) The heat pipe according to any one of (1) to (6), wherein the condenser section includes the first thick portion and the second thick portion in a cross section cut in a direction intersecting the extension direction of the tubular body. (8) The heat pipe according to (7), wherein the second thick portion of the intermediate section is connected to the second thick portion of the condenser section. (9) The heat pipe according to any one of (1) to (8), wherein the sintered body layer formed on the inner wall surface of the evaporator section is formed over the entire circumference in a cross section cut in a direction intersecting the extension direction of the tubular body.(10) A heat pipe according to any one of (1) to (9), wherein the sintered layer formed on the inner wall surface of the evaporator is formed over the entire length of the evaporator in the extension direction of the tube. (11) A heat pipe according to any one of (1) to (10), wherein the thickness of the combination of the tube and the sintered layer is gradually reduced from the evaporator side toward the condenser side. (12) An electronic device that accommodates in a housing a heat-generating component, a heat-dissipating component, a heat pipe including a tube that encloses a working fluid, and a sintered body layer formed by sintering metal powder on the inner wall surface of the tube, wherein the heat pipe includes an evaporation section where the working fluid evaporates due to heat from the heat-generating component, a condensation section where the working fluid condenses due to the heat dissipation effect of the heat-dissipating component, and an intermediate section located between the evaporation section and the condensation section, wherein at least the intermediate section includes a first thick section that is a first thickness and a second thick section that is a second thickness in a cross section cut in a direction intersecting the extension direction of the heat pipe, the second thickness being thicker than the first thickness, and at least a portion of the first thick section and the second thick section in the intermediate section are opposed to each other across the center of the tube in the cross section, and the second thick section is made of a combination of the tube and the sintered body layer. (13) The electronic device of (12), wherein at least a portion of the evaporation section is disposed in contact with the heat-generating component, and at least a portion of the condensation section is disposed in contact with the heat-dissipating component. (14) The electronic device of (12) or (13), wherein at least a portion of the second thick section is provided to be located at the bottom of the heat pipe when the electronic device is in a predetermined usage position. (15) The electronic device of any of (12) to (14), wherein the second thick section is provided to be located below the center of the tube in the up-down direction when the electronic device is in the predetermined usage position.(16) An apparatus used to form a sintered body layer in a heat pipe including a tube that encloses a working fluid and a sintered body layer formed by sintering metal powder onto the inner wall surface of the tube, the apparatus including: a first extension portion extending in the direction in which the tube extends; and a second extension portion extending from the end of the first extension portion in the direction in which the tube extends, wherein the length from the center of the second extension portion to the outer wall surface in a cross section taken in a direction intersecting the extension direction of the second extension portion is shorter than the length from the center of the first extension portion to the outer wall surface in a cross section taken in a direction intersecting the extension direction of the first extension portion, and the length from the center of the first extension portion to the outer wall surface in the cross section taken in the direction intersecting the extension direction of the first extension portion is partially shorter in the first extension portion. (17) The device of (16), wherein the second extension portion is cylindrical, and the outer wall surface of the first extension portion has a shape including a first outer peripheral surface with a first radius and a second outer peripheral surface with a second radius, the second radius being smaller than the first radius. (18) A method for manufacturing a heat pipe including a tube that encloses a working fluid and a sintered body layer formed by sintering a metal powder on the inner wall surface of the tube, the method including the steps of: inserting a device extending in the extension direction of the tube into the tube; filling a gap between the inner wall surface of the tube and the outer wall surface of the device with metal powder; and sintering the metal powder to form the sintered body layer in the gap, the gap including a first filling region and a second filling region, the second filling region having a width in the thickness direction of the tube wider than the first filling region, and the first filling region including a region that is partially wider in the thickness direction of the tube.

Claims

1. A heat pipe including a tube that encloses a working fluid and a sintered body layer that is formed by sintering a metal powder on an inner wall surface of the tube, an evaporation section in which the working fluid evaporates, a condensation section in which the working fluid condenses, and an intermediate section located between the evaporation section and the condensation section; Including, At least the intermediate portion includes, in a cross section cut in a direction intersecting an extension direction of the heat pipe, a first thick portion having a first thickness and a second thick portion having a second thickness, the second thickness being greater than the first thickness; At least a portion of the first thick portion and the second thick portion in the intermediate portion are opposed to each other across a center of the tube body on the cut surface, the second thick-walled portion is formed by a combination of the tube body and the sintered body layer, the first thick-walled portion is formed only by the tube body, At least the evaporation portion has a third thick portion having a third thickness, the third thick portion is formed by a combination of the tube body and the sintered body layer, and is thicker than the second thick portion; Heat pipe.

2. the intermediate portion includes the third thick portion in at least a part on the evaporation portion side; The heat pipe of claim 1 .

3. the third thick portion of the intermediate portion is connected to the third thick portion of the evaporation portion; The heat pipe according to claim 2 .

4. the condensation portion includes the first thick portion and the second thick portion in a cross section cut in a direction intersecting the extension direction of the pipe body. The heat pipe of claim 1 .

5. the second thick portion of the intermediate portion is connected to the second thick portion of the condensation portion; The heat pipe according to claim 4.

6. the sintered body layer formed on the inner wall surface of the evaporation section is formed over the entire circumference on a cross section cut in a direction intersecting the extension direction of the tubular body. The heat pipe of claim 1 .

7. The sintered body layer formed on the inner wall surface of the evaporation section is formed over the entire length of the evaporation section in the extension direction of the tubular body. The heat pipe according to claim 6.

8. a thickness of the combination of the tube body and the sintered body layer that gradually decreases from the evaporator side toward the condenser side; The heat pipe of claim 1 .

9. A heat-generating component; Heat dissipation components; a heat pipe including a tube that encloses a working fluid and a sintered body layer that is formed by sintering metal powder on an inner wall surface of the tube; An electronic device that accommodates the above in a housing, the heat pipe includes an evaporation section in which the working fluid is evaporated by heat from the heat-generating component, a condensation section in which the working fluid is condensed by the heat dissipation effect of the heat dissipation component, and an intermediate section located between the evaporation section and the condensation section, At least the intermediate portion includes, in a cross section cut in a direction intersecting an extension direction of the heat pipe, a first thick portion having a first thickness and a second thick portion having a second thickness, the second thickness being greater than the first thickness; At least a portion of the first thick portion and the second thick portion in the intermediate portion are opposed to each other across a center of the tube body on the cut surface, the second thick-walled portion is formed by a combination of the tube body and the sintered body layer, the first thick-walled portion is formed only by the tube body, At least the evaporation portion has a third thick portion having a third thickness, the third thick portion is formed by a combination of the tube body and the sintered body layer, and is thicker than the second thick portion; electronic equipment.

10. the evaporation portion is a portion that is disposed so as to be at least partially in contact with the heat-generating component, The condensation portion is a portion that is disposed so as to be in contact with the heat dissipation component at least in part.

10. The electronic device according to claim 9.

11. At least a part of the second thick portion is provided so as to be located at the lowest part of the heat pipe when the electronic device is in a predetermined usage posture.

10. The electronic device according to claim 9.

12. the second thick portion is provided so as to be located below a center of the tube in a vertical direction when the electronic device is in a predetermined usage posture.

10. The electronic device according to claim 9.

13. 1. A tool used to form a sintered body layer in a heat pipe including a tube that encloses a working fluid and a sintered body layer that is formed by sintering a metal powder on an inner wall surface of the tube, a first extension portion extending in the direction in which the tubular body extends; a second extension portion extending from an end of the first extension portion in the direction in which the pipe body extends; Including, a length from a center of the second extension portion to an outer wall surface in a cross section taken in a direction intersecting the extension direction of the second extension portion is shorter than a length from a center of the first extension portion to an outer wall surface in a cross section taken in a direction intersecting the extension direction of the first extension portion; the first extension portion has a cross section cut in a direction intersecting the extension direction of the first extension portion, the cross section having a length from a center of the first extension portion to an outer wall surface that is partially short, The outer peripheral surface of the portion where the length from the center to the outer wall surface of the first extension portion is partially short is shaped to fit along the inner wall surface of the tubular body. Equipment.

14. the second extension portion is cylindrical, the outer wall surface of the first extension portion has a shape including a first outer peripheral surface having a first radius and a second outer peripheral surface having a second radius, the second radius being smaller than the first radius; 14. The device of claim 13.

15. A method for manufacturing a heat pipe including a tube that encloses a working fluid and a sintered body layer that is formed by sintering a metal powder on an inner wall surface of the tube, inserting an instrument extending in the extension direction of the tubular body into the tubular body; a step of filling a gap between an inner wall surface of the tube body and an outer wall surface of the device with metal powder; forming the sintered layer in the gap by sintering the metal powder; Including, the gap includes a first filling region and a second filling region; The second filling region has a width in the thickness direction of the tube body that is wider than that of the first filling region, the first filling region includes a region that is partially wider in the thickness direction of the tube body, The outer circumferential surface of the partially wider region is shaped to fit the inner wall surface of the pipe body. A method for manufacturing a heat pipe.